On the hottest day of the summer of 1935, thirteen-year-old Briony Tallis sees her sister Cecilia strip off her clothes and plunge into the fountain in the garden of their country home. Watching her is Robbie Turner, her childhood friend. By the end of that day the lives of all three will have changed for ever and Briony will have committed a crime for which she will spend the rest of her life trying to atone.